Facility management entails the area of monitoring and controlling various facets of operating an industrial, commercial or residential establishment. These facets can include environmental systems, life safety and security systems, equipment systems, communication systems, and maintenance services.
When broadly considered, most facility management systems meet at least three operative criteria. First, the system monitors one or more facility management parameters. For instance, a system may monitor temperature, use or non-use of a particular device, or the opening or closing of a window.
Second, a facility management system will compare the monitored parameter with some preselected and desired status. Stated another way, the system must be able to determine whether a monitored temperature reading falls within an acceptable range, whether an operating piece of equipment should in fact not be operative or whether a window should be closed.
Third, a facility management system will interact with the facility such that the parameter being monitored may be affected. Continuing through with the examples provided above, the system might be required to initiate or deactivate a heating unit, close the open window, or deactivate the monitored equipment.
When a facility management system must exercise such control through physical movement, such as by opening a window or by closing a damper, one of two general methods of control are typically used: electronic and pneumatic.
Where rotational physical movement best serves the control function, then an electronic control system will generally prove most efficient. Where straight line movement provides better control capability, however, a pneumatic control system will often be preferred.
Typically, such straight line movement may be pneumatically accomplished by use of an airtight cylinder and piston arrangement. The introduction or release of pressurized air to or from the cylinder allows the piston to move back and forth. The piston operably connects to the controlled mechanism, and as the piston moves, the controlled mechanism may be appropriately manipulated.
At this point, a problem may be identified. Although pneumatic control mechanisms provide much better control than do electronic control mechanisms where straight line movement is required, typical control units that are suitable for use with pneumatic systems are often unsatisfactory. Such units are commonly viewed as deficient with respect to accuracy, flexibility, and reaction time. In contrast, electronic control units are very accurate, flexible and quick.
For certain applications, then, it would be desirable to provide a facility management system that included both an electronic control unit and a pneumatic cylinder arrangement. Such a system would borrow from the best of both systems. Unfortunately, the provision of an adequate interface between these two distinct system elements has been difficult. Prior art mechanisms that interface between an electronic control unit and a pneumatic cylinder unit tend to be complicated and expensive.
Furthermore, the interfacing solution should be one that can be harmoniously combined with an already installed pneumatic control system as where an operator seeks to upgrade an existing pneumatic control system with an electronic control unit.
In short, there is a need for a modulating unit that will successfully interface an electronic control unit and a pneumatic cylinder unit. Such a modulating unit should allow the complete system to gain the maximum benefits of both elements. Ideally, the modulating unit will be simple of manufacture and inexpensive to construct. Finally, the modulating unit should be of such design as to allow relatively simple upgrading of an existing pneumatic facility management system by parallel addition of an electronic control unit.